The present invention relates to a method for producing a ceramic long body. The method is applicable to, for example, a method for producing a ceramic tubular body used as a heat transmitting tube of a heat exchanger of a shell-and-tube type or the like.
A long ceramic member (hereinafter referred to as "ceramic long body") has been produced for use as a ceramic heat transmitting tube of a heat exchanger of a shell-and-tube type or the like. Such a ceramic long body is generally produced by forming a raw material powder into a compact having a predetermined long shape by various kinds of moldings, calcining the compact as. necessary, and firing the calcined ceramic body in such a state that the ceramic body is hung inside a sheath lest the ceramic body should directly touch the sheath.
When a ceramic member is produced, there arises a problem that a slight difference of density inside the compact is prone to deformation of the ceramic body in the firing process. The aforementioned conventional method for producing a ceramic long body has a problem that a ceramic long body is prone to having a warp particularly at the lower side thereof.
The reason the ceramic long body is prone to having a warp particularly at the lower side thereof seems to be as follows:
When the ceramic long body is fired in a state that the ceramic body is hung, the upper part of the ceramic long body is pulled downward by its own weight, and thereby a warp is formed. However, the lower part of ceramic long body hardly has such an inhibitory action. Recently, elongation of a heat transmitting tube has been investigated in developing a ceramic heat exchanger of a shell-and-tube type. Deformation of a ceramic tubular body to be used as a heat transmitting tube is one of impediments to achieving the elongation of the ceramic tubular body.